euglena/src/Shrink.java

import processing.core.*;
import static processing.core.PApplet.*;


class Shrink {
    float corner1x, corner1y, corner2x, corner2y, speed;
    int timeElapsed, millisInit;
    PImage shrinkRegion = null;

    private boolean corner1complete;

    Shrink(float speed) {
        this.speed = speed;
        this.corner1complete = false;
    }

    Shrink(float corner1x, float corner1y, float corner2x, float corner2y, float speed) {
        this.corner1x = corner1x;
        this.corner1y = corner1y;
        this.corner2x = corner2x;
        this.corner2y = corner2y;
        this.speed = speed;

        this.corner1complete = true;
    }

    float aspectRatio() {
        return abs((corner2x-corner1x)/(corner2y-corner1y));
    }

    float centerx() {
        return (corner1x + corner2x) / 2;
    }

    float centery() {
        return (corner1y + corner2y) / 2;
    }

    void saveShrinkRegion(ProjectorApplet p) {
        this.shrinkRegion = p.get(
                (int) p.convertXCoord(corner1x),
                (int) p.convertYCoord(corner1y),
                (int) abs(p.convertXDistance(corner2x-corner1x)),
                (int) abs(p.convertYDistance(corner2y-corner1y)));
    }

    ProjectorCommand makeProjectorCommand() {
        return (ProjectorApplet p) -> {
            if (shrinkRegion == null) {
                millisInit = p.millis();
                saveShrinkRegion(p);
            }

            timeElapsed = p.millis() - millisInit;

            if (p.convertXDistance(corner2x-corner1x) - speed * aspectRatio() * (timeElapsed/1000f) < 25) {
                return true;
            }

            p.noFill();
            p.noStroke();
            p.rectMode(CORNER);
            p.rect(p.convertXCoord(corner1x), p.convertYCoord(corner1y),
                    p.convertXDistance(corner2x - corner1x), p.convertYDistance(corner2y - corner1y));

            p.imageMode(CENTER);
            p.image(shrinkRegion, p.convertXCoord(this.centerx()), p.convertYCoord(this.centery()),
                    p.convertXDistance(corner2x - corner1x) - speed * aspectRatio() * (timeElapsed / 1000f),
                    p.convertYDistance(corner2y - corner1y) - speed * (timeElapsed / 1000f));

            return false;
        };
    }


    ClickGetter makeClickGetter(ProjectorApplet p){
        return (int x, int y) -> {
            if (!corner1complete){
                corner1x = x;
                corner1y = y;
                corner1complete = true;
                return false;

            } else {
                corner2x = x;
                corner2y = y;

                p.commandQueue.add(makeProjectorCommand());
                return true;
            }
        };
    }
}